Indeed, as I wrote in the piece:

Let’s get to the main point I want to emphasize today. I was surprised to learn, from Insidehook.com, that we are wrong when we think that our heart rates are optimally low. Ideally, we have high variability in heart rate — a low rate at rest and a high rate during exercise. High variability of your heart rate is a marker of good health.

Hope you have a great day, Wilson.